$5T sounds like a lot but it's spread over the lifetime of the panels, 20 years. What do utilities spend on capex and opex over 20 years.

Who’s “we”, you and the mouse in your pocket? The solar industry is getting that money, one homeowner, building owner, or lot owner at a time. And then, over time, they earn a profit in the generated energy! Sorry you hate making money doing nothing!

People will loan it and be paid back, with interest.